I'm always hearing people say that they want to have local docs like the ones at the Ruby Rdoc page. I've also wanted this and looked all over for a way to download these docs and haven't found them. Everyone says "Use Rdoc" but nothing more. I've only used rdoc on my own project and just didn't get what they were suggesting.
With Rdoc, it takes a few minutes to generate them, but you can make your own local copy of any Ruby docs. I think 90% of the Ruby/Rails world knows this already, but those of weren't in the secret, try this.
cd into your local directory that holds your Ruby/Rails code. This could be your own project code, /usr/local/lib/ruby/gems/1.8/gems/activerecord-1.15.3 (to generate your Active Record docs), or /usr/local/lib/ruby/1.8 (to build your own core Ruby docs). Since Ruby is interpreted, you've got all the system code right there on your own box.
Create a directory in your home folder called rdoc (or whatever you'll remember).
type rdoc -o ~/rdoc/activerecord or rdoc -o ~/rdoc/ruby or so on. Rdoc wants to create that last directory itself, so don't help it out by having it in place already.
When you're done, you'll have a nice, very fast, local copy of the docs. More importantly, you've created docs that match exactly what's installed on your machine.
It does take a few minutes to generate your own copy of the Ruby core docs, but the rest run fairly quickly.
